This invention relates to power-driven conveyors and, more particularly, to singulating conveyors including conveyor mats with article-supporting rollers for aligning a mass of conveyed articles into a single file.
Conventional singulating conveyors, or unscramblers, comprise a series of power-driven rollers arranged at an angle relative to a conveying direction. The rollers impart a component of force to conveyed articles transverse to the conveying direction. This transverse component of force pushes the articles toward one side of the conveyor as the flow of articles proceeds in the conveying direction. In some roller singulators, the articles are justified against a side wall; in other roller singulators, the articles are pushed to the center between two side-by-side beds of oppositely directed rollers. Rollers farther downstream rotate at higher speeds to separate articles from each other. But one of the problems with roller conveyors is that these all-metal conveyors can be noisy, especially as their bearings wear. Frequent maintenance, such as lubricating and tightening, and repair are a way of life with roller conveyors.
Conveyor belts, or chains, are used in unscramblers. In a conventional unscrambler, parallel side-by-side conveyor belts run at the same or progressively increasing speeds from belt to belt. A bar mounted at an angle to span the side-by-side belts deflects products and guides them along the bar toward a narrow single-file conveyor belt. But these belt conveyors are useful only for upstanding articles of known shape. Thin articles, such as mail envelopes or small packages, can wedge between the deflection bar and damage themselves or the conveyor. That""s why powered roller conveyors are used instead to singulate articles in the package-handling industry.
As these shortcomings of conventional roller singulators and belt unscramblers suggest, there is a need for a singulating conveyor that is less noisy than roller conveyors, yet capable of handling thin conveyed articles such as envelopes and small packages of various sizes.
These needs and others are satisfied by a singulating conveyor embodying features of the invention. One version of conveyor includes a first conveyor mat that extends in a lengthwise direction from a first end to a second end, in a widthwise direction from a first side to a second side, and in thickness from a top surface to a bottom surface. The first conveyor mat has a plurality of cavities opening onto its top and bottom surfaces. A roller is disposed in each cavity. Salient portions of each roller extend from the cavity past the top and bottom surfaces. Each roller is arranged to rotate about an axis oriented between the lengthwise and widthwise directions of the mat. A roller bearing surface disposed along the bottom surface of the first conveyor mat contacts the rollers. Relative motion between the rollers and the roller bearing surface causes the rollers to rotate and provide a sidewise component of motion to articles conveyed atop the rollers along the top surface of the first conveyor mat. A second conveyor mat adjacent to the first conveyor mat is arranged to receive articles from the first conveyor mat and to convey the articles at an increased speed in the lengthwise direction. Thus, the articles are aligned on the first conveyor mat and separated in the lengthwise direction along the conveyor carryway.
Another version of a conveyor suitable for singulating articles in a conveying direction comprises a first conveying zone and a second conveying zone downstream of the first conveying zone. A first conveyor mat in the first zone has rollers for supporting conveyed articles. The rollers are arranged to rotate about axes oblique to the conveying direction to provide a sideward component of motion transverse to the conveying direction. A second conveyor mat in the second conveying zone provides a component of motion in the conveying direction to the articles received from the first conveying zone. The component of motion in the conveying direction is greater in the second zone than in the first zone.
Yet another version of conveyor includes a centering belt and a separation belt. The centering belt has a central axis in the conveying direction that divides the belt into a left portion and a right portion. Rollers in the left portion are arranged to rotate about axes forming first acute angles with the central axis measured counterclockwise from the central axis. Rollers in the right portion are arranged to rotate about axes forming second acute angles with the central axis measured clockwise from the central axis. The separation belt is arranged downstream of the centering belt and operates at a speed sufficient to convey articles in the conveying direction faster than the articles proceed on the centering belt.
Still another version of conveyor includes a centering belt and a separation belt. The centering belt has rollers arranged to rotate about oblique axes as the belt travels in the conveying direction to direct conveyed articles toward a central axis of the belt. The separation belt, which is downstream of the centering belt, is operated at a speed sufficient to speed up the articles received from the centering belt and to separate them in the conveying direction.
In another version of singulator, the conveyor has first and second roller-top belts. The first roller-top belt lies on a first side of a conveyor centerline, and the second roller-top conveyor belt lies on the opposite second side of the centerline. Rollers in the first roller-top belt are arranged to rotate about axes parallel to a first oblique axis relative to the conveying direction. Rollers in the second roller-top belt are arranged to rotate about axes parallel to a second oblique axis. The roller arrangement is such that the rollers direct conveyed articles toward the centerline. A separation belt arrangement, downstream of the roller-top belts, is operated at a speed sufficient to speed up the conveyed articles to separate them in the conveying direction.
In one or more of these described versions, the conveyor mats may be stationary with a moving belt underneath to contact the rollers and rotate them. In other versions, the conveyor mats are conveyor belts driven in the direction of belt travel.